Discontinuously transmitting and receiving multimedia broadcast/multicast service data in mobile communication system

ABSTRACT

Discontinuous transmission and reception of point-to-multipoint service data between a network and a mobile terminal is achieved by transmitting scheduling information from the network to the mobile terminal via a first common channel. The mobile terminal determines a time for receiving the service data in response to the scheduling information and discontinuously receives the service data through a second common channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119(a), this application claims the benefit ofearlier filing date and right of priority to Korean Application No.2004-0009130, filed on Feb. 11, 2004, the contents of which is herebyincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multimedia broadcast/multicastbroadcast service (MBMS) in a mobile communication system and, moreparticularly, to discontinuously transmitting and receiving MBMS databetween a network and a mobile terminal.

2. Description of the Related Art

The universal mobile telecommunications system (UMTS) is athird-generation mobile communications system evolving from the globalsystem for mobile communications system (GSM), which is the Europeanstandard. The UMTS is aimed at providing enhanced mobile communicationsservices based on the GSM core network and wideband code-divisionmultiple-access technologies.

A related art UMTS network structure 1 is illustrated in FIG. 1. Amobile terminal, or user equipment (UE), is connected to a core network(CN) through a UMTS terrestrial radio access network (UTRAN). The UTRANconfigures, maintains, and manages a radio access bearer forcommunications between the UE 2 and the core network to meet end-to-endquality of service requirements.

The UTRAN includes a plurality of radio network subsystems (RNS), eachof which comprises one radio network controller (RNC) for a plurality ofbase stations, or “Node Bs.” The RNC connected to a given base stationis the controlling RNC for allocating and managing the common resourcesprovided for any number of UEs operating in one cell. One or more cellsexist in one Node B. The controlling RNC controls traffic load, cellcongestion, and the acceptance of new radio links. Each Node B mayreceive an uplink signal from a UE and may transmit downlink signals tothe UE. Each Node B serves as an access point enabling a UE to connectto the UTRAN, while an RNC serves as an access point for connecting thecorresponding Node Bs to the core network.

Among the radio network subsystems of the UTRAN, the serving RNC is theRNC managing dedicated radio resources for the provision of services toa specific UE and is the access point to the core network for datatransfer to the specific UE. All other RNCs connected to the UE aredrift RNCs, such that there is only one serving RNC connecting the UE tothe core network via the UTRAN. The drift RNCs facilitate the routing ofuser data and allocate codes as common resources.

The interface between the UE and the UTRAN is realized through a radiointerface protocol established in accordance with radio access networkspecifications describing a physical layer (L1), a data link layer (L2)and a network layer (L3) described in, for example 3GPP specifications.These layers are based on the lower three layers of an open systeminterconnection (OSI) model that is a well-known in the art ofcommunication systems. A related art architecture of the radio interfaceprotocol is illustrated in FIG. 2. As shown, the radio interfaceprotocol is divided horizontally into the physical layer, the data linklayer, and the network layer, and is divided vertically into a userplane for carrying data traffic such as voice signals and Internetprotocol packet transmissions and a control plane for carrying controlinformation for the maintenance and management off the interface.

The physical layer (PHY) provides information transfer service to ahigher layer and is linked via transport channels to a medium accesscontrol (MAC) layer. Data travels between the MAC layer and the physicallayer via a transport channel. Also, data transmission is performedthrough a physical channel between different physical layers, namely,between physical layers of a sending side (transmitter) and a receivingside (transmitter).

The MAC layer of the second layer provides a service to an upper layerof a radio link control (RLC) layer through a logical channel. The RLClayer provides support for reliable data transmissions, and may performa function of segmentation and concatenation of an RLC service data unit(SDU) coming from an upper layer.

The radio resource control (RRC) layer located at the lowest portion ofthe third layer (L3) is only defined in the control plane and controlstransport channels and physical channels with respect to theestablishment, re-establishment, and releasing of radio bearers. A radiobearer (RB) is a service provided by a lower layer, such as the RLClayer or the MAC layer, for transferring data between the UE and theUTRAN and guaranteeing a predetermined quality of service between the UEand the UTRAN.

The establishment of an RB determines regulating characteristics of theprotocol layer and channel needed to provide a specific service, therebyestablishing the parameters and operational methods of the service. Whena connection is established to allow transmission between an RRC layerof a specific UE and an RRC layer of the UTRAN, the UE is said to be inthe RRC-connected state. Without such connection, the UE is in an idlestate.

A UTRAN RRC layer requests one or more measurements from a terminal (UE)RRC in order to control a radio bearer. For example, the UTRAN RRC layerrequests the UE RRC to measure power of a channel transmitted in aspecific cell or to measure power of a channel transmitted from aspecific frequency.

Hereafter, a Multimedia Broadcast/Multicast Service (MBMS or “MBMSservice”) will be described. MBMS refers to a method of providingstreaming or background services to a plurality of UEs using an MBMSradio bearer that utilizes at least one of point-to-multipoint andpoint-to-point radio bearers. One MBMS service includes one or moresessions and MBMS data is transmitted to the plurality of terminalsthrough the MBMS radio bearer only while the session is ongoing. Here, asession is a time period during which particular data is sent by thenetwork.

As the name implies, an MBMS may be carried out in a broadcast mode or amulticast mode. The broadcast mode is for transmitting multimedia datato all UEs within a broadcast area, for example the domain where thebroadcast is available. The multicast mode is for transmittingmultimedia data to a specific UE group within a multicast area, forexample the domain where the multicast service is available.

The UTRAN provides the MBMS service to a plurality of UEs by using theRB. RBs used by the UTRAN can be classified as a point-to-point RB or apoint-to-multipoint RB. The point-to-point RB is a bi-directional RB,including a logical channel DTCH (Dedicated Traffic Channel), atransport channel DCH (Dedicated Channel) and a physical channel DPCH(Dedicated Physical Channel). Alternatively, the point-to-point RB mayinclude the DTCH, a transport channel FACH (Forward Access Channel) anda physical channel SCCPCH (Secondary Common Control Physical Channel).

The point-to-multipoint RB is a unidirectional downlink RB, including alogical channel MTCH (MBMS Traffic Channel), a transport channel FACH(Forward Access Channel), and the physical channel SCCPCH. The logicalchannel MTCH is configured for each MBMS service provided to one celland is used to transmit user plane data of a specific MBMS service tothe UEs.

The UTRAN providing the MBMS service transmits a control message,namely, an MBMS-related RRC message to the plurality of terminals (UEs)through an MCCH (MBMS Control Channel). The MBMS-related control messageincludes a message providing MBMS service information and a messageproviding point-to-multipoint RB information. As shown in FIG. 3, thelogical channel MCCH is the point-to-multipoint downlink channel and ismapped to the FACH, which is mapped to the SCCPCH. Only one MCCH existsin one cell.

Accordingly, when a terminal wants to receive a specific MBMS serviceusing the point-to-multipoint RB, it receives an RRC message includingRB information through the MCCH and sets a point-to-multipoint RB usingthe RB information. After the point-to-multipoint RB is set, theterminal continuously receives a physical channel SCCPCH, to which anMTCH is mapped, to obtain specific MBMS service data transmitted throughthe MTCH.

However, in the related art, because the terminal cannot recognize whenthe MBMS data is transmitted through the MTCH during a session, i.e.,the exact MBMS data transmission time, the terminal must continuouslyreceive the SCCPCH to which the MTCH is mapped during the session. Thus,the terminal is unable to perform other operations such as measuring achannel of a different cell during the session. In addition, when theterminal does perform the measurement operation, it cannot receive theMBMS data transmitted during the measurement operation.

SUMMARY OF THE INVENTION

The present invention is directed to a method for discontinuouslytransmitting and receiving MBMS data between a wireless system and amobile terminal.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, the presentinvention is embodied in a method for receiving a point-to-multipointservice in a mobile terminal of a mobile communication system, themethod comprising receiving scheduling information from a network fordiscontinuously receiving point-to-multipoint service data, wherein thescheduling information is provided via a first common channel to aplurality of mobile terminals subscribing to the point-to-multipointservice, determining a time for receiving the point-to-multipointservice data in response to the scheduling information, anddiscontinuously receiving the point-to-multipoint service data in themobile terminal through a second common channel.

The first common channel and the second common channel are mapped onto acommon physical channel. The scheduling information comprisesinformation associated with another common traffic logical channelmapped to the common physical channel. The scheduling information mayalso comprise information associated with another point-to-multipointservice data transmitted through the common physical channel. The firstcommon channel comprises a common control logical channel. The secondcommon channel comprises a common traffic logical channel.

In one embodiment of the present invention, the scheduling informationis received periodically, wherein the mobile terminal receives periodinformation for receiving the scheduling information through a thirdcommon channel. Furthermore, the scheduling information is receivedduring discontinued transmission of the point-to-multipoint servicedata.

In another embodiment of the invention, the scheduling information isreceived non-periodically, wherein the mobile terminal receivesinformation related to when the next scheduling information istransmitted through the first common channel. Moreover, the schedulinginformation is received during discontinued transmission of thepoint-to-multipoint service data.

In another aspect of the invention, the scheduling information comprisesinformation associated with discontinued transmission of thepoint-to-multipoint service data, wherein the mobile terminal suspendsreceiving the point-to-multipoint service data for a period associatedwith the scheduling information.

Alternatively, the scheduling information comprises informationassociated with continued transmission of the point-to-multipointservice data, wherein the mobile terminal receives thepoint-to-multipoint service data for a period associated with thescheduling information.

The scheduling information may further comprise information associatedwith a start time of the continued transmission of thepoint-to-multipoint service data, wherein the mobile terminal receivesthe point-to-multipoint service data from the start time for a periodassociated with the scheduling information.

In a detailed aspect of the invention, the scheduling informationcomprises a service identifier for identifying the point-to-multipointservice. The scheduling information may also comprise an identifier foridentifying the second common channel. The second common channel isconfigured in response to information transmitted through a third commonchannel.

In another aspect, the method further comprises selectively receivingthe scheduling information according to a scheduling information modeand receiving a mode indicator for indicating the scheduling informationmode, wherein the scheduling information mode comprises at least one ofreceiving the scheduling information once during discontinued receptionof the point-to-multipoint service data, receiving the schedulinginformation periodically during discontinued reception of the point-tomultipoint service data, and receiving the scheduling informationnon-periodically during discontinued reception of thepoint-to-multipoint service data. Preferably, the mode indicator isreceived through at least one of the first common channel, a thirdcommon channel using a point-to-multipoint RRC message, and a fourthcommon channel using system information.

A method for transmitting a point-to-multipoint service from a networkof a mobile communication system, comprises transmitting schedulinginformation to a mobile terminal for discontinuously receivingpoint-to-multipoint service data, wherein the scheduling information isprovided via a first common channel to a plurality of mobile terminalssubscribing to the point-to-multipoint service and discontinuouslytransmitting the point-to-multipoint service data in the mobile terminalthrough a second common channel.

The first common channel and the second common channel are mapped onto acommon physical channel, wherein the scheduling information comprisesinformation associated with another common traffic logical channelmapped to the common physical channel. The scheduling information mayfurther comprise information associated with another point-to-multipointservice data transmitted through the common physical channel. The firstcommon channel comprises a common control logical channel. The secondcommon channel comprises a common traffic logical channel.

In one embodiment of the invention, the scheduling information istransmitted periodically, wherein the network transmits periodinformation for transmitting the scheduling information through a thirdcommon channel. Furthermore, the scheduling information is transmittedduring discontinued transmission of the point-to-multipoint servicedata.

In another embodiment of the invention, the scheduling information istransmitted non-periodically, wherein the network transmits informationrelated to when the next scheduling information is transmitted throughthe first common channel. Furthermore, the scheduling information istransmitted during discontinued transmission of the point-to-multipointservice data.

In one aspect of the invention, the scheduling information comprisesinformation associated with discontinued transmission of thepoint-to-multipoint service data, wherein the network suspendstransmitting the point-to-multipoint service data for a periodassociated with the scheduling information.

In another aspect of the invention, the scheduling information comprisesinformation associated with continued transmission of thepoint-to-multipoint service data, wherein the network transmits thepoint-to-multipoint service data for a period associated with thescheduling information.

The scheduling information may further comprise information associatedwith a start time of the continued transmission of thepoint-to-multipoint service data, wherein the network transmits thepoint-to-multipoint service data from the start time for a periodassociated with the scheduling information.

In a further aspect of the invention, the scheduling informationcomprises a service identifier for identifying the point-to-multipointservice. The scheduling information may also comprise an identifier foridentifying the second common channel. The second common channel isconfigured in response to information transmitted through a third commonchannel.

In a detailed aspect of the invention, the method comprises transmittingthe scheduling information according to a scheduling information modeand transmitting a mode indicator for indicating the schedulinginformation mode, wherein the scheduling information mode comprises atleast one of transmitting the scheduling information once duringdiscontinued transmission of the point-to-multipoint service data,transmitting the scheduling information periodically during discontinuedtransmission of the point-to multipoint service data, and transmittingthe scheduling information non-periodically during discontinuedtransmission of the point-to-multipoint service data.

Preferably, the mode indicator is transmitted through at least one ofthe first common channel, a third common channel using apoint-to-multipoint RRC message, and a fourth common channel usingsystem information.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates a block diagram of a related art UMTS networkstructure.

FIG. 2 illustrates a block diagram of a related art radio accessinterface protocol based on 3GPP radio access network specifications.

FIG. 3 illustrates a related art MBMS channel mapping structure.

FIG. 4 illustrates an MBMS channel mapping structure in accordance withone embodiment of the invention.

FIG. 5 illustrates a timeline for discontinuously transmitting andreceiving MBMS data in a mobile communication system in accordance withone embodiment of the invention.

FIG. 6 illustrates a timeline for discontinuously transmitting andreceiving MBMS data in a mobile communication system in accordance withanother embodiment of the present invention.

FIG. 7 illustrates a timeline for discontinuously transmitting andreceiving MBMS data in a mobile communication system in accordance witha further embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is implemented in a mobile communication system,such as a UMTS (Universal Mobile Telecommunications System), which hasbeen developed according to 3GPP specifications. However, the presentinvention can also be applied to a different communications system.

The present invention relates to discontinuously transmitting andreceiving MBMS data between a network providing one or more MBMSservices and a mobile terminal receiving a specific MBMS. For thispurpose, the network system transmits an MBMS control message through afirst physical channel, and transmits MBMS data and an MBMS controlassist message (e.g. scheduling message) assisting the MBMS controlmessage through a second physical channel, to thereby discontinuouslytransmit the MBMS data to the mobile terminal according to the MBMScontrol assist message.

The mobile terminal receives the MBMS control message through the firstphysical channel, receives the MBMS data and the MBMS control assistmessage assisting the MBMS control message through the second physicalchannel, and discontinuously receives the MBMS data from the networkaccording to the control assist message.

The MBMS control assist message includes, for example, MBMS schedulinginformation for MBMS data transmitted through an MTCH and indicates thesuspension or resumption of an MBMS transmission or reception. If theMBMS scheduling information included in the MBMS control assist messageindicates suspension of the MBMS transmission or reception, the terminalsuspends reception of the MBMS data. If the MBMS scheduling informationindicates resumption of the MBMS transmission or reception, the terminalresumes reception of the MBMS data.

Furthermore, if the MBMS scheduling information of the MBMS controlassist message indicates suspension of transmission or reception of theMBMS data, the MBMS scheduling information additionally transferssuspension time information to the terminal. Preferably, the suspensiontime information includes a time for when the terminal suspendsreception of the MBMS data, a suspension period or a suspension offsetfor receiving the MBMS data.

The MBMS control message is transmitted through the logical channelMCCH. The MBMS data is transmitted through the logical channel MTCH. Thefirst physical channel is preferably the physical channel SCCPCH towhich the MCCH is mapped. The second physical channel is preferably thephysical channel SCCPCH to which the logical channel MTCH is mapped.

The MBMS control assist message is transmitted through a second physicalchannel to which the logical channel MTCH is mapped. The MBMS controlassist message is preferably transmitted through a logical channeldifferent from the MCCH. Preferably, the MBMS control assist messageincludes scheduling information indicating a control message transmittedthrough the first physical channel.

FIG. 4 illustrates an MBMS channel mapping structure in accordance witha preferred embodiment of the present invention. As shown in FIG. 4, inorder to discontinuously transmit and receive MBMS data, an S-MCCH(Secondary MCCH) assists the MCCH, wherein the S-MCCH is used totransmit the MBMS control assist message to the terminal. The logicalchannel S-MCCH is mapped to the transport channel FACH and the FACH ismapped to the physical channel SCCPCH. The S-MCCH is mapped to the sameSCCPCH to which the MTCH is mapped. Preferably, the S-MCCH is alwaysmapped to the same SCCPCH to which one or more MTCH are mapped.Furthermore, it is preferable that the S-MCCH not be mapped to the sameSCCPCH to which the MCCH is mapped.

Only one MCCH exists per cell, but comparatively, the number of S-MCCHsexisting per cell are as many as the number of SCCPCHs to which one ormore MTCHs are mapped. Preferably, one or more S-MCCHs exist in onecell. Further, a protocol stack of the S-MCCH is the same as a protocolstack of the MCCH.

Referring to FIG. 4, one MTCH is used to transmit the MBMS data for aspecific MBMS service. The S-MCCH transmits an MBMS control assistmessage related to the transmission and reception of the MTCH mapped tothe same SCCPCH as the S-MCCH. The MBMS control assist message includesMBMS scheduling information for the MBMS data transmitted through theMTCH, e.g., a transmission/reception indicator. The MBMS schedulinginformation is used to inform terminals desiring to receive a specificMBMS to suspend or resume reception of the MBMS through a specific MTCH.

The MBMS control assist message transmitted through the S-MCCH mayinclude MBMS scheduling information with an identifier for identifying aspecific MTCH (MTCH identifier) or an identifier for identifying an MBMStransmitted through the MTCH (MBMS identifier). Accordingly, the MBMSscheduling information can control the transmission/reception of MBMSdata transmitted through the MTCH by using the MTCH identifier or MBMSidentifier.

The operation of discontinuously transmitting/receiving MBMS data inaccordance with the present invention will now be described. Referringto FIGS. 5 to 7, a process is illustrated in which the UTRANdiscontinuously transmits specific MBMS data in units of TTI(Transmission Time Interval) through the SCCPCH and the terminaldiscontinuously receives the specific MBMS data through the SCCPCH.Herein, the units of TTI can be set at 10 ms, 20 ms, 40 ms or 80 ms.

FIG. 5 illustrates a timeline for discontinuously transmitting/receivingMBMS data between the UTRAN and the terminal in accordance with a firstembodiment of the present invention (mode 1). As shown in FIG. 5, theMBMS scheduling information indicating suspension is not repeatedlytransmitted during a suspension interval (S3) of MBMS data reception.

First, the network (for example, the UTRAN) transmits data through anSCCPCH to which a specific MTCH for a specific MBMS is mapped. The datais transmitted in units of TTI (Transmission Time Interval). Theterminal desiring to receive the MBMS receives the MBMS data through theSCCPCH (step S1).

If the data transmission is suspended for the specific MBMS servicethrough the specific MTCH, the UTRAN transmits an MBMS control assistmessage including MBMS scheduling information indicating suspension andan MBMS identifier (or a MTCH identifier) through the S-MCCH (step S2).

The terminal receives the MBMS control assist message including the MBMSscheduling information indicating suspension and the MBMS identifier (orthe MTCH identifier). The UTRAN may also include in the MBMS controlassist message time information at which MBMS scheduling informationindicating resumption of MBMS data transmission is transmitted. In thiscase, the terminal obtains from the MBMS control assist message the timeinformation at which the MBMS scheduling information indicatingresumption is transmitted.

Accordingly, the UTRAN suspends MBMS data transmission through the MTCHand the terminal suspends MBMS data reception through the MTCH accordingto the indication of the MBMS scheduling information included in theMBMS control assist message (step S3). During the data receptionsuspension interval, the terminal may perform various operations such asa measurement process according to an instruction of the UTRAN, receivethe MCCH, or receive a paging indicator channel for an MBMS.

In step S2, if time information at which the MBMS scheduling informationindicating resumption of the MBMS data transmission is to be transmittedis included in the MBMS control assist message, the terminal detects inthe MBMS control assist message the time information at which the MBMSscheduling information indicating resumption is transmitted from theUTRAN.

If, however, the time information at which the MBMS schedulinginformation indicating resumption is to be transmitted is not includedin the MBMS control assist message, the UTRAN transmits the timeinformation at which the MBMS scheduling information is to betransmitted through the MCCH or the paging indicator channel during thedata reception suspension interval.

Accordingly, the terminal can obtain the time information at which theMBMS scheduling information is to be transmitted and detect the timeinformation at which the MBMS scheduling information indicatingresumption of the MBMS data transmission is to be transmitted.

In this manner, the terminal can detect the time information at whichthe MBMS scheduling information indicating resumption is to betransmitted and suspend reception of the MBMS data through the SCCPCH towhich the MTCH is mapped until the MBMS scheduling informationindicating resumption is transmitted.

When the data transmission for the MBMS through the MTCH is resumed, theUTRAN transmits the MBMS control assist message including the MBMSscheduling information indicating resumption of the MBMS datatransmission and the MBMS identifier (or the MTCH identifier) to theterminal (step S4). Then, the terminal receives the MBMS control assistmessage and obtains the MBMS scheduling information indicatingresumption of the MBMS data transmission and the MBMS identifier (or theMTCH identifier).

If there is a time difference between the point at which the MBMSscheduling information indicating resumption is transmitted and thepoint at which MBMS data transmission through the MTCH is resumed, theUTRAN also includes information regarding an MTCH data transmissionresumption point in the MBMS control assist message. The terminalobtains the information regarding the MTCH data transmission resumptionpoint from the MBMS control assist message.

Accordingly, the UTRAN resumes the data transmission for the MBMSthrough the MTCH and the terminal resumes receiving the MBMS datathrough the MTCH according to the indication of the MBMS schedulinginformation indicating resumption (step S5).

In this case, if the received MBMS control assist message includes theinformation regarding the MTCH data transmission resumption point, theterminal starts receiving the MBMS data through the MTCH from the MTCHdata transmission resumption point. If, however, the MBMS control assistmessage does not include the information regarding the MTCH datatransmission resumption point, the terminal starts receiving the MBMSdata through the MTCH immediately after receiving the MBMS controlassist message including the MBMS scheduling information indicatingresumption.

FIG. 6 illustrates a timeline for discontinuously transmitting/receivingMBMS data between the UTRAN and the terminal in accordance with a secondembodiment of the present invention (mode 2). As shown in FIG. 6, theMBMS control assist message including the MBMS scheduling information isperiodically transmitted during the suspension interval of the datareception. For this purpose, the UTRAN should inform the terminal abouta transmission cycle of the MBMS scheduling information that isperiodically transmitted during the suspension interval of the datareception. The transmission cycle information of the MBMS schedulinginformation includes a cycle length with which the MBMS schedulinginformation is repeatedly transmitted during the suspension interval ofthe data reception. The cycle length refers to a time interval betweentwo successive MBMS scheduling information transmissions. In FIG. 6, thecycle length is equal to 5 TTI; i.e., five times a TTI length.

Referring to FIG. 6, the process of transmitting and receiving the MBMSdata between the UTRAN and the terminal is as follows. The UTRANtransmits specific MBMS data through the SCCPCH to which a specific MTCHis mapped in units of TTI. The terminal that desires to receive theMBMS, receives the MBMS data through the SCCPCH to which the MTCH ismapped (step S1).

If the MBMS data transmission through the MTCH is intended to besuspended, the UTRAN transmits an MBMS control assist message includingMBMS scheduling information indicating suspension of the MBMS datatransmission and the MBMS identifier (or MTCH identifier) through theS-MCCH (step S2). Here, the UTRAN also includes the transmission cycleinformation of the MBMS scheduling information in the MBMS controlassist message. Then, the terminal receives the MBMS control assistmessage and obtains the MBMS scheduling information indicatingsuspension of the MBMS data transmission and the MBMS identifier (orMTCH identifier). In this case, the terminal obtains the transmissioncycle information of the MBMS scheduling information from the MBMScontrol assist message.

The UTRAN suspends MBMS data transmission through the MTCH and theterminal suspends MBMS data reception through the MTCH according to theindication of the MBMS scheduling information included in the MBMScontrol assist message (step S3). During the suspension interval of thedata reception, the terminal can perform various operations such as ameasurement process according to an instruction of the UTRAN, receivethe MCCH, or receive a paging indicator channel for an MBMS.

The UTRAN periodically transmits the MBMS control assist messageincluding the MBMS scheduling information through the S-MCCH during thesuspension interval of the data reception (step S4). If the transmissioncycle information of the MBMS scheduling information is included in theMBMS control assist message in the step S2, the terminal obtains thetransmission cycle information of the MBMS scheduling information fromthe MBMS control assist message and detects a point at which the MBMSscheduling information is periodically transmitted.

If, however, the transmission cycle of the MBMS scheduling informationis not included in the MBMS control assist message, the terminalreceives the transmission cycle information of the MBMS schedulinginformation through the BCCH or the MCCH before performing the step S4.

After obtaining a point at which the MBMS scheduling information isperiodically transmitted, the terminal suspends reception of the MBMSdata through the MTCH and receives the MBMS scheduling informationthrough the S-MCCH periodically.

In addition, during the suspension interval of the data reception, theUTRAN periodically transmits the MBMS scheduling information through theS-MCCH (step S5). Meanwhile, the terminal suspends MBMS data receptionthrough the MTCH and periodically receives the MBMS schedulinginformation through the S-MCCH by using the transmission cycleinformation of the MBMS scheduling information obtained in the step S4.

Thereafter, when the MBMS data transmission through the MTCH is to beresumed, the UTRAN sets the MBMS scheduling information to indicateresumption of the MBMS data transmission and transmits an MBMS controlassist message including the MBMS scheduling information indicatingresumption and the MBMS identifier (or the MTCH identifier) to theterminal through the S-MCCH (step S6).

If there is a time difference between the point at which the MBMSscheduling information indicating resumption is transmitted and thepoint at which data transmission of the MBMS through the MTCH isresumed, the UTRAN also includes information regarding an MTCH datatransmission resumption point in the MBMS control assist message. Theterminal obtains the information regarding the MTCH data transmissionresumption point from the MBMS control assist message.

Accordingly, the UTRAN resumes data transmission of the MBMS through theMTCH and the terminal resumes reception of the MBMS data through theMTCH according to the indication of the control assist message includingthe MBMS scheduling information indicating resumption of the MBMS datatransmission that has been received in the step S6 (step S7).

If the MBMS control assist message received in the step S6 includes theinformation regarding the MTCH data transmission resumption point, theterminal starts receiving the MBMS data through the MTCH from the MTCHdata transmission resumption point as indicated by the information. If,however, the MBMS control assist message received in the step S6 doesnot include information regarding the MTCH data transmission resumptionpoint, the terminal starts receiving the MBMS data through the MTCHimmediately after receiving the MBMS control assist message includingthe MBMS scheduling information indicating resumption.

FIG. 7 illustrates a method of discontinuously transmitting/receivingMBMS data between the UTRAN and the terminal in accordance with a thirdembodiment of the present invention (mode 3). As shown in FIG. 7, theMBMS control assist message including the MBMS scheduling information isnon-periodically transmitted during the suspension interval of the datareception. For this purpose, if the MBMS control assist messagetransmitted during the suspension interval of the data receptionincludes the MBMS scheduling information, the UTRAN also includestransmission point information regarding the next MBMS schedulinginformation transmission transmitted in a corresponding MBMS controlassist message.

Preferably, the MBMS control assist message including the MBMSscheduling information includes transmission point information of theMBMS scheduling information to be transmitted next. Preferably, thetransmission point information of the MBMS scheduling information to betransmitted next includes time difference (offset) information between atransmission point of the MBMS control assist message including the MBMSscheduling information being currently transmitted and a transmissionpoint of the MBMS control assist message including the MBMS schedulinginformation to be transmitted next.

For example, in the step S2 of FIG. 7, the MBMS control assist messageincluding the MBMS scheduling information indicating suspension of theMBMS data transmission includes an offset value of 7. The offset valueis the time difference between the transmission point of the MBMSscheduling information in the step S2 and the transmission point of theMBMS scheduling information in the step S4.

In this manner, the MBMS control assist message including the MBMSscheduling information indicating suspension transmitted in the step S4includes an offset value of 4. The offset value indicates the timedifference between the transmission point of the MBMS schedulinginformation in the step S4 and the transmission point of the MBMSscheduling information in the step S5.

In the same manner, the MBMS control assist message including the MBMSscheduling information indicating suspension transmitted in the step S5includes an offset value of 5, wherein the offset value indicates thetime difference between the transmission point of the MBMS schedulinginformation in the step S5 and the transmission point of the MBMSscheduling information in the step S6.

Such a method can be also applied to a MBMS control assist messageincluding MBMS scheduling information indicating resumption of the MBMSdata transmission. The MBMS control assist message including the MBMSscheduling information indicating resumption transmitted in the step S6of FIG. 7 includes an offset value of 3. The offset value indicates thetime difference between the transmission point of the MBMS schedulinginformation in the step S6 and the resumption point of the datatransmission of the MBMS through the MTCH that follows immediately.

The process of transmitting/receiving specific MBMS data between theUTRAN and the terminal will now be described. The UTRAN transmits theMBMS data through a specific SCCPCH to which a specific MTCH is mappedin units of TTI. The terminal that desires to receive the MBMS, receivesthe MBMS data through the SCCPCH to which the MTCH is mapped (step S1).

If the data transmission for the MBMS through the MTCH is to besuspended during the data transmission, the UTRAN transmits an MBMScontrol assist message including MBMS scheduling information indicatingsuspension of the MBMS data transmission, an MBMS identifier (or a MTCHidentifier) and an offset value through the S-MCCH (step S2). Here, theoffset value is equal to 7. The terminal receives the MBMS controlassist message and obtains the MBMS scheduling information indicatingsuspension, the MBMS identifier (or the MTCH identifier) and the offsetvalue.

Thereafter, the UTRAN suspends the data transmission of the MBMS datathrough the MTCH and the terminal suspends receiving the MBMS datathrough the MTCH according to the indication of the MBMS schedulinginformation included in the MBMS control assist message (step S3).During the suspension interval of the data reception, the terminal mayperform various operations such as a measurement process according to aninstruction of the UTRAN, receive the MCCH, or receive a pagingindicator channel for an MBMS.

The UTRAN transmits the next MBMS control assist message including theMBMS scheduling information, the MBMS service identifier (or the MTCHidentifier) and the offset value through the S-MCCH during thesuspension interval (step S4). The terminal detects the nexttransmission point of the MBMS control assist message including the MBMSscheduling information by using the offset value (offset=7) obtained inthe previous step S2, and receives the corresponding MBMS control assistmessage at the indicated transmission point.

Preferably, since the offset value obtained by the terminal in the stepS2 is 7, the terminal suspends reception of the SCCPCH to which thespecific MTCH is mapped during 6 TTIs. After the seventh TTI, theterminal receives the MBMS control assist message including the MBMSscheduling information of the current step S4. In addition, the terminalalso obtains a new offset value (offset=4) included in the MBMS controlassist message received in the current step S4.

The UTRAN then transmits the next MBMS control assist message includingthe MBMS scheduling information, the MBMS identifier (or the MTCHidentifier) and an offset value through the S-MCCH during the suspensioninterval of the data reception (step S5). In this case, the terminalreceives the MBMS control assist message including the MBMS schedulinginformation being currently transmitted according to the new offsetvalue (offset=4) obtained in the previous step S4. The terminal alsoobtains the new offset value (offset=5) included in the MBMS controlassist message received in the current step S5.

Thereafter, if data transmission of the MBMS through the MTCH is to beresumed, the UTRAN sets the MBMS scheduling information to indicate theresumption of the MBMS data transmission and then transmits the MBMScontrol assist message including the corresponding MBMS schedulinginformation and the MBMS identifier (or the MTCH identifier) to theterminal through the S-MCCH (step S6).

If there is a time interval between the point at which the MBMSscheduling information indicating resumption is transmitted and thepoint at which the MBMS data transmission through the MTCH is resumed,the UTRAN also includes in the MBMS control assist message informationrelating to an MTCH data transmission resumption point, such as anoffset value. In this case, the terminal obtains the informationregarding the MTCH data transmission resumption point, namely, theoffset value, from the MBMS control assist message. Here, the offset hasa value of 3.

Accordingly, the UTRAN resumes the data transmission of the MBMS throughthe MTCH and the terminal resumes receiving the MBMS data through theMTCH according to the indication of the MBMS control assist messageincluding the MBMS scheduling information indicating resumption asreceived in the step S6 (step S7).

If the MBMS control assist message received in the step S6 includes theinformation regarding the MTCH data transmission resumption point,namely, the offset value (offset=3), the terminal starts receiving theMBMS data through the MTCH from the MTCH data transmission resumptionpoint indicated by the offset.

For example, as shown in FIG. 7, when the offset value is equal to 3,the terminal receives the MBMS control assist message including the MBMSscheduling information indicating resumption and the MTCH datatransmission resumption point at the step S6. The terminal then resumesreceiving the MBMS data through the MTCH after suspending receptionduring 2 TTIs.

If the MBMS control assist message received in the step S6 does notinclude the information regarding the MTCH data transmission resumptionpoint, the terminal resumes receiving the MBMS data through the MTCHimmediately after receiving the MBMS control assist message includingthe MBMS scheduling information indicating resumption.

In the present invention, for the sake of explanation, three types ofdiscontinuous transmission/reception methods have been described inthree different embodiments (modes). The three types of discontinuoustransmission/reception methods can be selectively used, for which theUTRAN should transmit information regarding the selected embodiment(mode) to the terminal. Namely, the UTRAN may transmit a mode indicatorto the terminal.

The UTRAN transmits the mode indicator and the terminal operates duringthe suspension interval of the data reception according to a modeindicated by the received mode indicator. The operations of the terminalaccording to each mode have been described with reference to FIGS. 5 to7.

The UTRAN can transmit the mode indicator to the terminal throughvarious logical channels. First, a UTRAN RRC can transmit the modeindicator to a terminal RRC by using system information through theBCCH. Second, the UTRAN RRC can transmit the mode indicator to theterminal RRC by using an MBMS RRC message through the MCCH. Third, theUTRAN RRC can transmit the mode indicator to the terminal RRC throughthe S-MCCH.

Preferably, when the mode indicator is transmitted to the terminalthrough the S-MCCH, the UTRAN RRC transmits the mode indicator to theterminal RRC using the MBMS control assist message including the MBMSscheduling information indicating suspension of the MBMS datatransmission. Specifically, the UTRAN RRC transmits the mode indicatorto the terminal RRC by using the MBMS control assist message includingthe MBMS scheduling information indicating suspension most adjacent tothe MTCH data transmission. Namely, the UTRAN RRC uses the MBMS controlassist message including the MBMS scheduling information indicatingsuspension in the step S2 of FIGS. 5 to 7.

For example, in the step S2 of FIGS. 5 to 7, the UTRAN includes the modeindicator in the MBMS control assist message including the MBMSscheduling information indicating suspension and then transmits it tothe terminal. Accordingly the terminal receives the MBMS control assistmessage including the mode indicator and then operates during thesuspension interval of the data reception according to a mode indicatedby the corresponding mode indicator.

As so far described, the method for discontinuously receiving the MBMSdata in accordance with the present invention has many advantages. Forexample, a wireless system transmits an MBMS control assist messagethrough a physical channel transmitting MBMS data and transmits MBMSdata discontinuously using the MBMS control assist message. A mobileterminal receives the MBMS control assist message through the physicalchannel and then receives the MBMS data discontinuously according to theMBMS control assist message.

Therefore, the mobile terminal can receive the MBMS data or performmeasurement operations effectively. Namely, the terminal can easilyperform a measurement operation while the MBMS service is beingprovided. Thus, the problem of the related art wherein the terminalcannot receive the MBMS data while the measurement operation isperformed is solved.

Although the present invention is described in the context of mobilecommunication, the present invention may also be used in any wirelesscommunication systems using mobile devices, such as PDAs and laptopcomputers equipped with wireless communication capabilities. Moreover,the use of certain terms to describe the present invention should notlimit the scope of the present invention to a certain type of wirelesscommunication system. The present invention is also applicable to otherwireless communication systems using different air interfaces and/orphysical layers, for example, TDMA, CDMA, FDMA, WCDMA, etc.

The preferred embodiments may be implemented as a method, apparatus orarticle of manufacture using standard programming and/or engineeringtechniques to produce software, firmware, hardware, or any combinationthereof. The term “article of manufacture” as used herein refers to codeor logic implemented in hardware logic (e.g., an integrated circuitchip, Field Programmable Gate Array (FPGA), Application SpecificIntegrated Circuit (ASIC), etc.) or a computer readable medium (e.g.,magnetic storage medium (e.g., hard disk drives, floppy disks, tape,etc.), optical storage (CD-ROMs, optical disks, etc.), volatile andnon-volatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs,SRAMs, firmware, programmable logic, etc.).

Code in the computer readable medium is accessed and executed by aprocessor. The code in which preferred embodiments are implemented mayfurther be accessible through a transmission media or from a file serverover a network. In such cases, the article of manufacture in which thecode is implemented may comprise a transmission media, such as a networktransmission line, wireless transmission media, signals propagatingthrough space, radio waves, infrared signals, etc. Of course, thoseskilled in the art will recognize that many modifications may be made tothis configuration without departing from the scope of the presentinvention, and that the article of manufacture may comprise anyinformation bearing medium known in the art. The foregoing embodimentsand advantages are merely exemplary and are not to be construed aslimiting the present invention. The present teaching can be readilyapplied to other types of apparatuses. The description of the presentinvention is intended to be illustrative, and not to limit the scope ofthe claims. Many alternatives, modifications, and variations will beapparent to those skilled in the art. In the claims, means-plus-functionclauses are intended to cover the structure described herein asperforming the recited function and not only structural equivalents butalso equivalent structures.

1. A method for receiving a point-to-multipoint service in a mobile terminal of a mobile communication system, the method comprising: receiving scheduling information from a network for discontinuously receiving point-to-multipoint service data, wherein the scheduling information is provided via a first common channel to a plurality of mobile terminals subscribing to the point-to-multipoint service; determining a time for receiving the point-to-multipoint service data in response to the scheduling information; and discontinuously receiving the point-to-multipoint service data in the mobile terminal through a second common channel.
 2. The method of claim 1, wherein the first common channel and the second common channel are mapped onto a common physical channel.
 3. The method of claim 2, wherein the scheduling information comprises information associated with another common traffic logical channel mapped to the common physical channel.
 4. The method of claim 2, wherein the scheduling information comprises information associated with another point-to-multipoint service data transmitted through the common physical channel.
 5. The method of claim 1, wherein the first common channel comprises a common control logical channel.
 6. The method of claim 1, wherein the second common channel comprises a common traffic logical channel.
 7. The method of claim 1, wherein the scheduling information is received periodically.
 8. The method of claim 7, wherein the mobile terminal receives period information for receiving the scheduling information through a third common channel.
 9. The method of claim 7, wherein the scheduling information is received during discontinued transmission of the point-to-multipoint service data.
 10. The method of claim 1, wherein the scheduling information is received non-periodically.
 11. The method of claim 10, wherein the mobile terminal receives information related to when the next scheduling information is transmitted through the first common channel.
 12. The method of claim 10, wherein the scheduling information is received during discontinued transmission of the point-to-multipoint service data.
 13. The method of claim 1, wherein the scheduling information comprises information associated with discontinued transmission of the point-to-multipoint service data.
 14. The method of claim 13, wherein the mobile terminal suspends receiving the point-to-multipoint service data for a period associated with the scheduling information.
 15. The method of claim 1, wherein the scheduling information comprises information associated with continued transmission of the point-to-multipoint service data.
 16. The method of claim 15, wherein the mobile terminal receives the point-to-multipoint service data for a period associated with the scheduling information.
 17. The method of claim 1, wherein the scheduling information further comprises information associated with a start time of the continued transmission of the point-to-multipoint service data.
 18. The method of claim 17, wherein the mobile terminal receives the point-to-multipoint service data from the start time for a period associated with the scheduling information.
 19. The method of claim 1, wherein the scheduling information comprises a service identifier for identifying the point-to-multipoint service.
 20. The method of claim 1, wherein the scheduling information comprises an identifier for identifying the second common channel.
 21. The method of claim 1, wherein the second common channel is configured in response to information transmitted through a third common channel.
 22. The method of claim 1, further comprising: selectively receiving the scheduling information according to a scheduling information mode; and receiving a mode indicator for indicating the scheduling information mode; wherein the scheduling information mode comprises at least one of: receiving the scheduling information once during discontinued reception of the point-to-multipoint service data; receiving the scheduling information periodically during discontinued reception of the point-to multipoint service data; and receiving the scheduling information non-periodically during discontinued reception of the point-to-multipoint service data.
 23. The method of claim 22, wherein the mode indicator is received through at least one of: the first common channel; a third common channel using a point-to-multipoint RRC message; and a fourth common channel using system information.
 24. A method for transmitting a point-to-multipoint service from a network of a mobile communication system, the method comprising: transmitting scheduling information to a mobile terminal for discontinuously receiving point-to-multipoint service data, wherein the scheduling information is provided via a first common channel to a plurality of mobile terminals subscribing to the point-to-multipoint service; and discontinuously transmitting the point-to-multipoint service data in the mobile terminal through a second common channel.
 25. The method of claim 24, wherein the first common channel and the second common channel are mapped onto a common physical channel.
 26. The method of claim 25, wherein the scheduling information comprises information associated with another common traffic logical channel mapped to the common physical channel.
 27. The method of claim 25, wherein the scheduling information comprises information associated with another point-to-multipoint service data transmitted through the common physical channel.
 28. The method of claim 24, wherein the first common channel comprises a common control logical channel.
 29. The method of claim 24, wherein the second common channel comprises a common traffic logical channel.
 30. The method of claim 24, wherein the scheduling information is transmitted periodically.
 31. The method of claim 30, wherein the network transmits period information for transmitting the scheduling information through a third common channel.
 32. The method of claim 30, wherein the scheduling information is transmitted during discontinued transmission of the point-to-multipoint service data.
 33. The method of claim 24, wherein the scheduling information is transmitted non-periodically.
 34. The method of claim 33, wherein the network transmits information related to when the next scheduling information is transmitted through the first common channel.
 35. The method of claim 33, wherein the scheduling information is transmitted during discontinued transmission of the point-to-multipoint service data.
 36. The method of claim 24, wherein the scheduling information comprises information associated with discontinued transmission of the point-to-multipoint service data.
 37. The method of claim 36, wherein the network suspends transmitting the point-to-multipoint service data for a period associated with the scheduling information.
 38. The method of claim 24, wherein the scheduling information comprises information associated with continued transmission of the point-to-multipoint service data.
 39. The method of claim 38, wherein the network transmits the point-to-multipoint service data for a period associated with the scheduling information.
 40. The method of claim 24, wherein the scheduling information further comprises information associated with a start time of the continued transmission of the point-to-multipoint service data.
 41. The method of claim 40, wherein the network transmits the point-to-multipoint service data from the start time for a period associated with the scheduling information.
 42. The method of claim 24, wherein the scheduling information comprises a service identifier for identifying the point-to-multipoint service.
 43. The method of claim 24, wherein the scheduling information comprises an identifier for identifying the second common channel.
 44. The method of claim 24, wherein the second common channel is configured in response to information transmitted through a third common channel.
 45. The method of claim 24, further comprising: transmitting the scheduling information according to a scheduling information mode; and transmitting a mode indicator for indicating the scheduling information mode; wherein the scheduling information mode comprises at least one of: transmitting the scheduling information once during discontinued transmission of the point-to-multipoint service data; transmitting the scheduling information periodically during discontinued transmission of the point-to multipoint service data; and transmitting the scheduling information non-periodically during discontinued transmission of the point-to-multipoint service data.
 46. The method of claim 45, wherein the mode indicator is transmitted through at least one of: the first common channel; a third common channel using a point-to-multipoint RRC message; and a fourth common channel using system information. 